Packaging Bag with Tearing Aid

ABSTRACT

The invention relates to a packaging bag with a tearing aid, with which it is reliably provided that the packaging bag is opened in a defined way by manual tearing by the user, so that no packaging contents are lost. The packaging bag is essentially made from a front and a back, which are connected to each other in their edge regions with a material fit and which thus forms a joint edge, in which an opening notch is formed, whose center line intersects two weakened lines at an intersection point starting at a distance from the notch tip. These weakened lines each extend across the width of the front and the back. The direction of the weakened line at the intersection point encloses, with the center line, a tear angle greater than 0° and less than 90°.

FIELD OF THE INVENTION

The invention relates to a packaging bag made from a flexible one-layeror multi-layer packaging material, such as, paper, plastic, and/ormetal, with a tearing aid that allows defined tearing of the packagingbag.

BACKGROUND OF THE INVENTION

The necessity of defined tearing of a packaging bag, when such a bag isopened by manual tearing without the use of any tool, is especiallyimportant if the package contents involve such materials as liquid, bulkmaterial, or a plurality of small parts, so that the packaging contentspartially or completely escape as a result of uncontrolled opening ofthe packaging bag.

The packaging size and the packaging material of packaging bagsaccording to the class are defined as a function of the type andquantity of the package contents and can be very different. Thesepackaging bags can indeed differ in shape, but, in the broadest sense,they always involve a packaging bag with a front and a back, which areconnected to each other in their edge region with a material fit. Theconnection can already exist over a part of the edge region due to afolding of the blank for the packaging bag. The other parts of the edgeregion are connected to each other by adhesion or fusion over a givenedge width (called joint edge below).

Upon vertical positioning or holding of the packaging bag, for which thelabeling on the packaging bag contains adequate instruction, a hollowspace forms in the upper region of the bag volume free of the packagingcontents. In this region, the front and the back can be at leastpartially brought into contact with each other when they are pressedtogether. So that no packaging contents are lost as the package is beingtorn, the tear line that is being formed, starting from the edge regionbordering the hollow space, may extend only across the regions of thefront and back that border the hollow space. However, without a tearingaid, most materials do not always tear in the desired regions.

Examples for packaging bags according to the invention will be discussedbelow.

For packaging building materials, such as cement, frequently a two-layerpackaging material is used that consists of a plastic film, which facesthe interior of the bag and which serves the purpose of merelyprotecting the packaging contents from moisture, and a verytear-resistant, robust paper layer that faces the exterior of the bagand which reliably withstands both the weight of the packaging contentsitself, which, in the case of cement, can exceed 30 kg, and thetransport loads. The bag shape here is a typical sack shape defined byan upper edge, a lower edge, and two side edges. The side edges, andoften the lower edge, are formed here by means of creases. The upperedge is a joint edge with a typical edge width of ca. 1-4 cm.

Rather than weight, but instead requirements for hygiene and longstorage life for the packaging contents are important for packages inthe food and beverage industry. Particularly for beverage packages,three-layer packaging materials are used consisting of an outer, printedpaper or plastic layer, a metal layer, and an inner plastic layer. Here,the typically rectangular bag shapes are often bonded or fused to eachother along all of the edges, i.e., the packages have a peripheral jointedge, with a typical edge width of about 2-8 mm.

The packaging material for such items as individually packaged sweets isoften only a single-layer plastic film, which is produced, for example,as a tube and which has a lower and an upper joint edge.

In principle, the packaging material is produced in webs or sheets andfinished into individual blanks. The blanks are then folded orpreformed, and edges lying one on top of another are fused or bonded toeach other so that a packaging bag is formed that is completely closedafter being filled.

A joint edge is always produced, so that the packaging materials lyingdirectly one on another are connected to each other across a given edgewidth. The joint edge can be a peripheral, closed edge or can beinterrupted by creases.

Packaging bags that have an I-shaped or V-shaped opening notch in alateral joint edge are widely known. Then, for opening, the packagingbag can be gripped at the joint edge on both sides of the opening notchand pulled apart. The tear is started in the notch direction and shouldprogress through the packaging material in the notch direction, which,however, does not happen in practice if the tear is not guided in thisdirection.

From practice, solutions are also known in which weakened lines areformed across the width of the front and/or back of the packaging bag,whereby a tear progression is indeed guided, but there is the difficultyof starting the tear at the beginning of the weakened line.

The introduction of an opening notch and a weakened line, which opensinto the end of the opening notch, appears to bring together theadvantages of both alternatives currently known from past practice.However, to implement this in industrial mass production is verydifficult technically, because the two cannot take place in one process,where the opening notch must be positioned exactly relative to theweakened line.

No solutions have been presented that combine an opening notch in theedge region and a weakened line running across the width of a packagingbag.

The formation of a weakened line can take place, in practice, onlybefore the folding or shaping of the packaging bag. Ideally, it isformed into the material web before it is partitioned into blanks forthe packaging bag.

The weakened lines can be a partial material separation, a partialmaterial removal, or also embossing along the line course of the desiredweakened line.

A partial material separation can be a deep cut that does not completelyseparate the material, for example, produced with a knife or a stamp.

A partial material removal can be an incomplete separating groove or aperforation or slit line of partially or completely penetratingperforations or slots, or combinations of these.

The formation of an opening notch, in practice, can only be made afterthe fusing or adhesion of the edge regions. Here, the depth of the notchmay not be greater than the width edge of the formed joint edge. Tofulfill the mentioned requirements, this processing step must becontrolled as a function of the position of the weakened line. Meansmust be provided that detect the position of the weakened line, in orderto control signals that can be derived from these means as controlparameters for the positioning of the packaging bag relative to theprocessing tool for the opening notch, which would be very complicated.

SUMMARY OF THE INVENTION

The invention is based on the problem of creating a packaging bag with afront and a back connected by a joint edge, in which, for guiding atear, an opening notch and weakened lines are formed for guided tearprogression.

This problem is solved by a packaging bag with the features set forth inclaim 1.

Advantageous improvements are described in the subordinate claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of a packaging bag according to the present invention will bedescribed in more detail below in connection with the annexed drawings,in which:

FIG. 1 a shows a first embodiment in top view;

FIG. 1 b shows a material web with the blank for the first embodiment;

FIG. 1 c shows a cutout from FIG. 1 a;

FIG. 2 shows a second embodiment;

FIG. 3 shows a third embodiment;

FIG. 4 shows a fourth embodiment;

FIG. 5 shows a fifth embodiment;

FIG. 6 shows a sixth embodiment;

FIG. 7 shows a seventh embodiment;

FIG. 8 shows a packaging bag with triangular front and back;

FIG. 9 shows a packaging bag with additional base part; and

FIG. 10 shows a packaging bag with different front and back sides.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

As is known from practice, packaging bags according to the inventionhave a front 1 and a back 2, which are at least partially fused orbonded to each other in their edge regions. The edge regions bonded orfused to each other form joint edges 3 of a predetermined edge width.

In FIG. 1 a, a first embodiment of a packaging bag according to theinvention is shown in top plan view onto the front 1. The front 1 andthe back 2, lying behind the front, have a rectangular shape and areconnected to each other by means of a peripheral joint edge 3.

A blank 4 for this packaging bag, shown in FIG. 1 b, is advantageouslycut to length from a web of packaging material and has twice the widthof the packaging bag. Through folding along the center line, the front 1and the back 2 are placed so that one overlaps the other. The creaseformed by the fold forms one of the two side edges. Connecting the otherside edge and the bottom edge would be sufficient to create a packagingbag that can be filled. To achieve an overall symmetric impression or tobe able to adequately grip the packaging bag peripherally, however, as arule the edge region along the crease is also formed as a joint edge 3.

It is clear to someone skilled in the art that the blank 4 can also beshaped in such a way that the front 1 and the back 2 can overlap bymeans of the bottom edge or also the upper edge. In the latter variant,filling would then be performed from below.

The shape of the two sides need not necessarily be rectangular oridentical. For example, in addition to FIGS. 1 to 7, in which the shapeof the packaging bag is rectangular, at least in the tear region, FIG. 8shows a packaging bag with two identical triangular side surfaces, FIG.9 shows a packaging bag with two identical trapezoidal side surfaces anda third round surface forming a base. In a packaging bag according toFIG. 10, the front side is trapezoidal, and the back is rectangular. Athird surface forming a base creates the equalization for the edges ofdifferent lengths of the front and the back.

All of the embodiments for a packaging bag according to the inventionhave the following in common:

an opening notch 5 is provided in a joint edge 3;

two weakened lines 6 are provided across the width of the packaging bag,more precisely, the front 1 and the back 2, wherein these weakened lines6 divide the packaging bag into an upper bag part 9 and a lower bag part10; and

the center line 7 of the opening notch 5 intersects the weakened lines 6at an intersection point 8 at an angle greater than 0° and less than 90°(referred to herein as tear angle α) outside of the opening notch 5 at adistance “a” from the notch tip.

The combination of an opening notch 5 with weakened lines 6 in themanner described represents a tearing aid and is essential to theinvention.

A special advantage of this tearing aid lies in its simple production.

It is technically simple to produce an opening notch 5 and the weakenedlines 6 with the given conditions because the introduction of theopening notch 5 need not be oriented exactly to the position of thealready given weakened lines 6. In particular, if the opening notch 5 islocated in the upper bag part 10, it can deviate considerably from itsdesired position relative to the weakened line 6, without this havingsignificant effects on the tear behavior. In FIG. 8, examples ofpermissible position deviations are shown.

By spreading apart the regions bordering the opening notch 5, as knownfrom practice, a tear is introduced by means of the notch tip. The tearpropagates from the notch tip in an uncontrolled way in the front 1 andthe back 2 of the packaging bag until it meets the weakened lines 6 atan intersection point 8. Strictly speaking, as it leaves the joint edge3, i.e., at the end of the material connection between the front 1 andthe back 2, the spreading tear divides into two tears. Because theyspread in an uncontrolled way, they could also meet the weakened lines 6at different intersection points 8. However, in order not tounnecessarily complicate the description of the invention, only one tearis referred to below, which, starting from the notch tip, meets theweakened lines 6 at an intersection point 8.

From there, the progression of the tear is guided along the weakenedlines 6, that is, the packaging bag is separated in a defined way into alower bag part 9 and an upper bag part 10, apart from a negligibly shortpath. The separation line defines the opening edge of the lower bag part9 that is formed. Through a selected guidance of the weakened lines 6,which form the separation line, the opening edge can be advantageouslyformed for discharging or pouring out the packaging contents.

The weakened lines 6 need not be identical in their line course on thefront 1 and on the back 2. Also, the distance “a” and the intersectionpoint 8 need not be identical, relative to the front 1 or the back 2.However, in order not to unnecessarily complicate the description of theinvention, a congruent line layout shall be assumed, which has the samespacing “a” and the same intersection point 8 on the front 1 and theback 2. An identical line layout is advantageous for the tear behavior,because both weakened lines 6 should be separated simultaneously underthe action of a tear force.

Certain advantageous parameter variations of a packaging bag accordingto the invention are discussed hereinbelow.

Essentially, the positioning of the opening notch 5, the opening angle,and the depth of the opening notch 5, the line layout of the weakenedline 6, and its formation, the tear angle α and the distance “a” canvary.

The opening angle of the opening notch 5 has significance only insofaras the opening notch 5 can be better visually detected with a largeropening angle. For fulfilling its function, the opening notch 5 can alsobe limited to a narrow slot.

The depth of the opening notch 5 must be selected so that the notch tipstill lies completely in the joint edge 3. For an opening notch 5 whosecenter line 7 meets the edge of the joint edge 3 at a right angle, thismeans that the depth of the opening notch 5 is smaller than the edgewidth of the joint edge 3. The opening notch 5, however, is at leastdeep enough that the packaging material can be separated by a moderatetearing force up to the intersection point 8 with the weakened lines 6.

For the tearing behavior, the tear angle α should be as small aspossible. Indeed, the reliability of the tear intersecting the weakenedlines 6 increases when the tear angle α is larger, but for a small tearangle α, the component of the tearing force in the direction of theweakened line 6 increases as the tear angle α decreases. Preferably, thetear angle α should therefore be greater than 10° and less than 45°.

The distance “a” should be as small as possible. However, if it isselected too small, then position deviations of the opening notch 5 fromits desired position could have the effect that the center line 7intersects the desired line in the opening notch 5. A tear propagatingfrom the notch tip would then not intersect the weakened lines 6.

The weakened lines 6 can be produced by any known material attenuationthat can be realized along a line. In particular, the weakened line 6can be

-   -   a continuous cut line with a constant or variable depth of cut,    -   a line of slits or perforations or combinations of these, which        are separated by connecting pieces and penetrate or do not        penetrate the material,    -   a stamped line, or    -   a line along which the packaging material has different material        properties.

In FIGS. 1-10, the weakened lines 6 are each shown as dashed lines,which represent all of the mentioned embodiments.

As tools for production, typical tools for material separation, materialremoval, or material modification can be used.

A laser appears to be especially well suited. The possibilities in theselection of a laser with a wavelength suitable for the correspondingpackaging material, the adaptation of the laser parameters to thedesired material attenuation, and also the variable controllability ofthe laser radiation, such as, by means of a robot arm or a scanner, makea laser the tool of choice and a lased weakened line a preferredimplementation of a weakened line 6.

The weakened lines 6 divide the packaging bag into a lower bag part 9and an upper bag part 10. When the packaging bag is completely torn, theupper bag part 10 is separated from the lower bag part 9, and thepackaging contents should be located completely in the lower bag part 9.

The line course of the weakened lines 6 is preferably straight, angled,or curved, wherein changes in direction should be as continuous aspossible.

In the first embodiment of a packaging bag shown in FIGS. 1 a-1 c, theweakened lines 6 have an angled line layout, and these weakened linescorrespond to the three edges of the peripheral line of an isoscelestrapezoid. The opening notch 5 is formed in the joint edge 3 bordering aside edge, wherein the center line 7 is at a right angle to the sideedge. At the intersection point 8, the direction of the line course ofthe weakened lines 6 encloses, with the side edge and thus also thecenter line 7, a tear angle α of greater than 0° and less than 90°, ca.45° here, for example. The distance “a” is selected so that a tearintroduced via the opening notch 5 intersects the weakened lines 6outside of the joint edge 3. If the distance “a” is selected to be toolarge, then there is the risk that the progressing tear will spread inan uncontrolled way into the lower bag part 9 and, thus, a definedopening would no longer be possible, even before it intersects theweakened lines 6.

In a second embodiment shown in FIG. 2, the distance “a” is reduced inorder to increase the reliability that an introduced tear actuallyintersects the weakened lines 6 and does not run away from these linesin an uncontrolled way. The intersection point 8 still lies within thejoint edge 3. This has the effect that the guidance of the progressingtear still starts within the joint edge 3. Instead of an abrupt changein direction according to FIG. 1 a, the line layout of the weakened line6 has a continuous change in angle, due to the rounding of the angledline layout.

Like all of the embodiments described below, the third embodiment shownin FIG. 3 differs from the two aforementioned embodiments in that theopening notch 5 is not formed within the lower bag part 9, but insteadwithin the upper bag part 10.

This has the advantage that a tear that progresses from the notch tip ofthe opening notch 5 intersects each of weakened lines 6 completelyindependently of the distance a.

In this third embodiment, the lateral edge regions are not formed as ajoint edge 3, but instead are delimited exclusively by creases. Here,the packaging bag is closed across its length, as shown, on the back 2.The opening notch 5 is located in the joint edge 3 bordering the upperedge of the packaging bag.

The fourth embodiment, shown in FIG. 4, has a sinusoidal line course ofthe weakened lines 6. Therefore, the open edge of the lower bag part 9(bag opening) is constructed in such a way that the valley of thesinusoid forms a spout in the front 1 and the back 2. Because the spoutsare not exactly opposite in the periphery of the bag opening, liquidpackaging contents will be emptied exclusively through one of thespouts, as long as it is held at the lowest point.

In the fifth embodiment shown in FIG. 5, the line course of the weakenedlines 6 is again a sinusoid, which is shifted by a half period relativeto that in FIG. 4, so that the weakened lines 6 taper off into a valleyat the side edges. Here, the valleys could also be used as spouts, inparticular, the one opposite the opening notch 5. The opening notch 5 ishere formed again in the joint edge 3, bordering a side edge, and isnevertheless located in the upper bag part 10.

Such a construction appears to be especially advantageous because, bymeans of the opening notch 5 in the upper bag part 9, it is assured thatthe tear will intersect the weakened line 6, that the packaging contentscan be easily emptied and that the user can tear the packaging bag inthe usual way, starting from one side edge.

The advantage of a sinusoidal line layout or another periodic linelayout also lies in its simple realizability, such as, by means of alaser scanner.

In FIGS. 6, 7, and 8, embodiments are shown in which the line layout ofthe weakened lines 6 corresponds to a straight line. So that theweakened lines 6 and the center line 7 of the opening notch 5nevertheless intersect each other at a tear angle α, the opening notch 5in the sixth embodiment shown in FIG. 6 is formed at a corner, whereinthe joint edge 3 limited here would have a wider construction.

In the seventh embodiment disclosed in FIG. 7, the opening notch 5 wouldbe formed at an angle to the side edge, i.e., the center line 7 is notperpendicular to the side edge.

In the embodiment shown in FIG. 8, as already explained, the front 1 andthe back 2 are triangular surfaces, which is why an opening notch 5formed perpendicular to the side edge intersects a straight weakenedline 6 running across the width of the packaging bag at a tear angle α.In such a solution, the tear angle α. equals the vertex angle of thetriangle, here 35°. Alternative locations for the opening notch areshown at (5).

The smaller the tear angle α, the more easily the tear can transitioninto the weakened line 6.

List of reference symbols

-   -   1 Front    -   2 Back    -   3 Joint edge    -   4 Blank    -   5 Opening notch    -   6 Weakened line    -   7 Center line of the opening notch    -   8 Intersection point    -   9 Lower bag part    -   10 Upper bag part    -   α Tear angle    -   a Distance

While the invention has been illustrated and described in connectionwith currently preferred embodiments shown and described in detail, itis not intended to be limited to the details shown since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention. The embodiments werechosen and described in order to best explain the principles of theinvention and practical application to thereby enable a person skilledin the art to best utilize the invention and various embodiments withvarious modifications as are suited to the particular use contemplated.

1. Packaging bag with tearing aid, comprising a front and a back, saidfront and back being connected to each other at least partially in theiredge regions with a material fit thereby defining a joint edge of agiven edge width, an opening notch formed in said joint edge, and twoweakened lines which extend across the width of the packaging bagdefining a tearing region on the front and the back and which divide thepackaging bag into an upper bag part and a lower bag part, wherein anextension of a center line of said opening notch intersects saidweakened lines at an intersection point at a distance from the tip ofsaid notch outside of said notch forming a tear angle with said weakenedlines of greater than 0° and less than
 900. 2. Packaging bag accordingto claim 1, wherein said front and said back have a rectangular form atleast in said tearing region, and said opening notch is formed on one ofthe side edges, and wherein said center line of said opening notchextends perpendicular to a side edge, and wherein the direction of theline layout of said weakened lines at said intersection point enclosesan angle greater than 0° and less than 90° with said side edge. 3.Packaging bag according to claim 2, wherein the course of said weakenedlines represents an angled straight line.
 4. Packaging bag according toclaim 2, wherein the course of said weakened lines is a sinusoid. 5.Packaging bag according to claim 1, wherein said front and said backhave a rectangular form at least in said tearing region, wherein saidopening notch is formed on one of the side edges of said bag, andwherein said center line of said opening notch extends at an anglegreater than 0° and less than 90° relative to said side edge, the courseof said weakened lines is a straight line.
 6. Packaging bag according toclaim 1, wherein said front and said back have, at least in said tearingregion, the shape of an isosceles triangle, and said opening notch isformed on one of said side edges of said bag, wherein said center lineof said opening notch extends perpendicular to a side edge, and thedirection of the course of said weakened lines at said intersectionpoint encloses, with said side edge, an angle greater than 0° and lessthan 90°.
 7. Packaging bag according to claim 1, wherein said front andsaid back have the shape of an isosceles triangle, at least in saidtearing region, and said opening notch is formed on one of the sideedges of said bag, wherein said center line of said opening notchextends at an angle greater than 0° and less than 90° relative to saidside edge, and the course of the weakened lines is a straight line. 8.Packaging bag according to claim 1, wherein said opening notch is in theupper bag part.
 9. Packaging bag according to claim 1, wherein saidintersection point lies within said joint edge.
 10. Packaging bagaccording to claim 1, wherein said tear angle is greater than 10° andless than 45°.
 11. Packaging bag according to claim 1, wherein saidweakened line is a lased line.